Highlights from this report include: for the period January 1984 - December 1986, mentions for cocaine in emergency room (ER) drug-abuse related episodes increased for the total Drug Abuse Warning Network (DAWN) system, the 26 metropolitan areas in DAWN, and national panel of ERs; no metropolitan areas saw a decrease in cocaine mentions; mentions for heroin/morphine increased in the overall DAWN system, in the national panel, and in 11 of the 26 metropolitan areas; a decrease for heroin/morphine mentions was noted in New Orleans; mentions for marijuana increased in the total DAWN system and 7 of the 26 areas, while marijuana mentions decreased over the 3-year period in Cleveland, Indianapolis, and Los Angeles; 7 of the 26 areas noted increases in PCP/PCP combinations, while 3 areas showed decreases in PCP/PCP combination mentions. In drug-abuse related medical examiner (ME) cases, drug abuse deaths involving cocaine increased from 184 in the second half of 1983 to 563 in the first half of 1986; and heroin/morphine mentions increased from 438 as of December 1983 to 934 as of June 1986. This report presents trends in the semiannual number of mentions of selected drugs in ER drug-abuse related episodes for the period January 1984 - December 1986 and drug-abuse related ME cases for the period July 1983 - June 1986, as reported through the DAWN system. Data were obtained from 661 participating ERs and 75 MEs or coroners in 26 metropolitan areas in the continental United States. Trends in drug mentions are tabulated for 6-month intervals over a 3-year period. Tables and appendixes